A Highland Park home that caught fire over the weekend, leaving one person critically injured, had at least nine occupants and no working smoke detectors, fire Chief Patrick Tanner said.

An electric space heater in the basement — where two makeshift bedrooms had been set up with plywood walls and mattresses on the floor, apparently in violation of local laws — is being eyed as the likely cause of the blaze, city officials said.

No citations had been issued as of Tuesday, and authorities still were trying to sort out whether the rental property violated zoning laws that limit the number of people who can live in a home, based in part on its size. City officials also are trying to determine who is responsible for any violations — the landlord, the tenants or both — and what penalties could come.

But the blaze at 581 Glenview Ave. has reopened talk among city leaders about instituting an ordinance for rental housing that could include mandatory landlord registration, annual inspections and steeper penalties for noncompliance. Though zoning, building and housing codes already exist, city leaders say they've struggled to enforce them with leased housing because of a lack of regular inspections.

Mayor Nancy Rotering called the situation "appalling."

Speaking of the larger issue of rental property regulation, the mayor said: "Our job as a city is to keep our residents safe. If some property owners do not feel that responsibility toward their tenants, it is time for us to make it their responsibility."

Firefighters responded to the two-story house about 4:25 a.m. Saturday and, using thermal imaging equipment, Tanner said, located an unconscious man in the basement with severe inhalation burns. The man remained in critical condition Tuesday at Loyola University Medical Center in Maywood, the chief said. Another man had second-degree burns and was treated and released over the weekend.

Tanner said it appears that nine to 13 people were living at the house. Had the fire not been contained to the basement, he said, it could have been worse.

The person who appears to own the property, based on county records, could not be reached for comment.

The property had no previous reported violations or recent inspections, according to electronic records dating to 2004, said Scott Moe, Highland Park's building division manager.

"This is the same thing the City Council has discussed in the past," Tanner said, regarding the potential code violations. "We could have very easily had multiple fatalities. We still may have one."

The council has made plans to discuss the matter at a committee-of-the-whole meeting Jan. 13.

Moe said it's a violation of zoning code to have bedrooms in a residential basement, and the property maintenance code requires working smoke detectors.

The house must be brought up to code before it can be inhabited again, he said.

"It's certainly a topic of conversation as to where we're going … especially given the outcome," Moe said. "It's horrendous."

Highland Park has property maintenance and housing codes. But enforcement is the difficult part, Moe said. As it is now, inspections of rental dwellings generally are triggered by tenant complaints, field observations of the building's exterior or when an owner requests a permit for a building addition.

In September, the City Council began discussing a new rental housing ordinance that could increase the number of inspections for rental properties and require their owners to register with the city. Currently, the city does not have a quick or direct way to contact property owners, and tax bills acquired from the county don't always help, as they're often addressed to limited liability companies whose owners aren't always easy to track down.

"Who do I call? Mr. LLC?" Moe said. "I have what I believe to be the owner's information, but I'm not positive."

The difficult balance of a rental housing ordinance would be holding landlords accountable without displacing tenants who are living in unacceptable conditions, Rotering said.

"Fair housing must be safe housing," she said.

Residents using space heaters this winter should take extra caution, the fire chief said, using only appropriate power sources and keeping the heaters away from flammable items.